Segregation That No One Seeks

This paper examines a series of Schelling-like models of residential segregation, in which agents prefer to be in the minority. We demonstrate that as long as agents care about the characteristics of their wider community, they tend to end up in a segregated state. We then investigate the process that causes this, and conclude that the result hinges on the similarity of informational states amongst agents of the same type. This is quite different from Schelling-like behavior, and suggests (in his terms) that segregation is an instance of macro behavior which can arise from a wide variety of micro motives. Weak, individually-held preferences can be significantly amplified when aggregated in a population. This fact is exemplified in simple agent-based models of segregation, that show how weak preferences to have like individuals as neighbors leads to far greater segregation than any individual desires. In his landmark studies of this phenomenon1, Thomas Schelling represented a neighborhood as a grid with two types of agents placed randomly on it. Each agent was allowed to move to nearby unoccupied cells in order to satisfy its preference to be like at least thirty percent of its neighbors. Despite the relatively low preference for having neighbors of the same type, these models exhibit significant segregation and clustering of the agents. This phenomenon has become known as the Schelling result or Schelling segregation.